Milling machine for longitudinal profiled elements

ABSTRACT

The present invention relates to a machine intended for the machining of profiled elements ( 10 ), of the type comprising a longitudinal frame ( 1 ) provided with holding dollies ( 11, 13 ) for holding the profiled element to be machined ( 10 ). This machine is characterized in that it comprises at least two holding dollies ( 11, 13 ) capable, in the machining, of securing the slide-holding of the profiled element ( 10 ), and at least one drive dolly ( 15, 17 ), in which the profiled element ( 10 ) is slide-mounted, this drive dolly ( 15, 17 ) being provided with a device for securing its temporary fixed connection to the profiled element ( 10 ) such that the relative displacement of the latter relative to the machining head ( 9 ) in the longitudinal direction (yy′) is secured, at least in part, by the displacement of this drive dolly ( 15, 17 ).

FIELD OF THE INVENTION

The present invention relates to a machine intended for the machining oflongitudinal profiled elements, especially by the removal of chips.

BACKGROUND OF THE INVENTION

Machines intended for the machining of such profiled elements, which areconstituted by two assemblies, namely a milling assembly comprising amachining head movable along three axes, vertical, longitudinal andtransverse, and an assembly of two dolly carriages, which are eachcapable of admitting the profiled elements in sliding and clampingarrangement and of positioning them angularly relative to the machininghead. During the machining operation, the dollies secure the holding ofthe profiled element and, in order to do so, are fixedly connectedthereto. These dollies are disposed at a certain distance apart which isa function of the rigidity dictated by the type of machining to beperformed. This spacing thus defines a work window representing themaximum machining length which the machine will be able to perform inone step, so that, in order to machine the whole of the rod, an approachbased on successive steps is adopted.

In order to simplify the restart procedures necessary between each step,it has been proposed to combine with these dollies one or moreadditional dollies. These dollies, while realizing a holding withreference to the profiled element, secure the displacement of the latterbetween the different machining phases corresponding to the differentsuccessive steps.

Such devices only permit a step-by-step machining of the profiledelement, wherein the step length may not exceed the width of the windowdefined by the spacing of the two dollies, this spacing itself being afunction of the precision of the desired machining.

BRIEF DESCRIPTION OF THE INVENTION

The object of the present invention is to eliminate these drawbacks byproposing a metal-working machine by which a fully continuous machiningof such profiled elements can be realized.

The subject of the present invention is thus a machine intended for themachining of longitudinal profiled elements, of the type comprising alongitudinal frame provided with holding dollies for holding theprofiled element to be machined and provided with at least one machininghead which can be moved relative to the profiled element according todisplacement components which are preferably perpendicular to each otherand perpendicular to the longitudinal axis of said profiled element,which machine comprises:

-   -   at least two holding dollies disposed close to and on either        side of the machining head, which are capable, in the machining,        of securing the slide-holding of the profiled element,    -   at least two drive dollies capable of moving longitudinally        relative to the frame, disposed on either side of the holding        dollies, each drive dolly being provided with a chuck by which,        according to requirement, a sliding clamping of the profiled        element or a locking of this profiled element can be secured        such that the relative displacement of the latter relative to        the machining head in the longitudinal direction is secured, at        least in part, by the displacement of a drive dolly,    -   control means for operating the displacements of the drive        dollies and of the chucks, these control means being capable, as        a function of the various machining phases to be realized, of        securing the driving of the profiled element with the aid of one        or more drive dollies and of synchronizing the movements of the        drive dollies,    -   characterized in that the control means are designed to operate,        in a machining operation, a fixed-connection fastening onto the        profiled element of a dolly in the end position and a        slide-fastening of the other drive dolly, and to secure the        relative longitudinal displacement of the profiled element by        operating its displacement through that of the dolly to which it        is fixedly connected and which then forms a “dominant” dolly,        and when the “dominant” dolly arrives close to the holding        dolly, the control means, on the one hand, operate the        separation of the dolly from the profiled element and, on the        other hand, the fixed connection of the other drive dolly, which        then becomes the “dominant” dolly, to the profiled element and        which dolly secures the relative longitudinal displacement of        the profiled element, whilst the first drive dolly is returned        to position ready to become “dominant” again.

Preferably, at least the holding dollies will be provided with a rotarychuck comprising a clamping device for the profiled element capable ofsecuring its positioning about its longitudinal axis.

Finally, it has proved beneficial, in order to realize certain types ofmachining, for the machining head to comprise displacement means actingin the longitudinal direction of the profiled element.

BRIEF DESCRIPTION OF THE FIGURES

An embodiment of the present invention will be described below, by wayof non-limiting example, with reference to the appended drawing, inwhich:

FIG. 1 is a diagrammatic perspective view of an embodiment of ametal-working machine according to the invention,

FIGS. 2 to 4 are diagrammatic views of the machine according to theinvention represented in FIG. 1, in which the drive dollies have beenpositioned on the bed in certain characteristic positions which they arelikely to occupy in the course of a machining stage.

DETAILED DESCRIPTION OF THE INVENTION

The metal-working machine according to the invention, represented inFIG. 1, comprises a longitudinal bed 1, which supports a crosspiece 3fixed substantially to the centre of the bed 1. This crosspiece 3supports a saddle 5, which is provided with cross-drive means operatedby numeric control means 7. The saddle 5 itself supports a machininghead 9, which is mounted such that it is vertically movable under thecontrol of the numeric control means 7. The machining head 9 is thuscapable of moving in the transverse, vertical and, possibly,longitudinal directions.

The bed 1 is likewise provided with four dollies, namely two holdingdollies 11 and 13, disposed on either side of the machining head 9, andtwo drive dollies 15 and 17, disposed on either side of the holdingdollies. The drive dollies 15, 17, as well as the holding dollies 11,13, can be moved longitudinally on the bed 1 under the control ofnumeric control means 16. Their movement can be made in a totallymutually independent manner or, conversely, in a perfectly synchronizedmanner and this according to their control program.

In a known manner, the holding dollies 11, 13 and the drive dollies 15,17 are equipped with variable-pressure chucks by which, according torequirement, a locking and a clamping of a profiled element 10 or,conversely, a sliding clamping of the latter, and this as a function ofinstructions provided by the numeric control means 16, can be secured.The chucks are equipped with means by which the profiled element 10 canbe rotated about its longitudinal axis yy′ and with reference means bywhich the profiled element 10 can be positioned relative to the saidlongitudinal axis.

The working of the machine according to the invention is as described inthe following example.

The profiled element 10 is firstly introduced into the four dollies insuch a way that it comes into contact with the provided reference,thereby securing its angular positioning relative to the longitudinalaxis yy′, then the holding dollies 11 and 13 are positioned at a slightdistance apart such as to promote a better machining quality. The chucksof these dollies are clamped onto the profiled element 10 such that theydo not to lock it but allow it slide displacement.

If, for example, the passage of the profiled element 10 proceeds fromright to left in the figure, according to the arrow D, the drive dolly17 (right-hand dolly) is initially positioned in the extreme rightposition of the bed 1, as represented diagrammatically in FIG. 2, andthe drive dolly 15 (left-hand dolly) is initially positioned against theholding dolly adjacent thereto, namely the dolly 11.

According to the invention, the numeric control means 16 in this caseoperate a fixed-connection fastening of the dolly 17 on the profiledelement 10 and a slide-fastening of the drive dolly 15 on the profile.

The machining operation is then started, in the course of which therelative longitudinal displacement of the profiled element 10 relativeto the tool 9 is secured by operating its displacement through that ofthe dolly 17 to which it is fixedly connected and which then forms aso-called “dominant” dolly. It will be noted that if the direction ofdisplacement of the profiled element in the course of machining is thedirection D, that does not preclude the drive dollies, for certain partsof this machining phase, from securing an instantaneous displacement ofthe profiled element 10 in the reverse direction. When, as representedin FIG. 3, the dominant dolly 17 arrives close to the holding dolly 13,on the one hand the separation of the dolly 17 from the profiled element10 is operated, via the numeric control means 16, so that this dollythen ceases to be dominant, and, on the other hand, the drive dolly 15is fixedly connected to the profiled element 10, so that it is thisdolly which then becomes the dominant dolly and secures the relativelongitudinal displacement D of the profiled element 10 relative to themachining head 9. During the cycle in which the drive dolly 15 isdominant, the drive dolly 17 is returned towards the right of the bed(displacement in the direction E in FIG. 4), where it is then ready tobecome dominant again as soon as the drive dolly 15 reaches the end ofits travel, that is to say, for example, once it is at the left end ofthe bed 1.

According to the invention, the continuous character of the displacementof the profiled element 10 when the drive dolly 17 reaches the end ofits travel, especially when it arrives close to the holding dolly 13,can be improved. In such an embodiment, the profiled element 10 is inthis case driven with the two drive dollies 15 and 17. Then, when thismovement is perfectly underway, the separation of the dolly 17 isoperated, which then ceases to be dominant, and it is returned toposition in the rightward direction, as previously mentioned.

With the aid of numeric control means 16 and through the synchronizationof the instructions given to the actuating means for the dollies, theycan thus be used in such a way that the passage of the profiled element10 in the longitudinal direction is effected perfectly continuously. Inone particular machining phase, it is possible, as previously mentioned,for the two drive dollies to act simultaneously as dominant dollies.Such will be the case, for example, when there is a need to realize amachining pass which calls for a considerable force.

The present invention is particularly interesting not only in that itprovides a totally continuous displacement of the profiled element,thereby avoiding the problems of restarting the machining, but also byvirtue of the fact that this continuous displacement can be realized onprofiled elements of whatever length.

The machine according to the invention can also, in a simplifiedversion, only comprise a single drive dolly.

In these conditions, when the dominant dolly is close to the holdingdolly adjacent thereto, all longitudinal displacement of the profiledelement 10 is halted for the period needed to return the drive dolly tothe end of the bed, after having separated it from the profiled element.

In certain cases, which will be specific to the machining range, it willbe possible to take advantage of a phase which does not require alongitudinal drive to return the dolly, in masked time, to the end ofthe bed.

1. A machine intended for the machining of longitudinal profiledelements (10), of the type comprising a longitudinal frame (1) providedwith holding dollies (11, 13) for holding the profiled element to bemachined (10) and provided with at least one machining head (9) whichcan be moved relative to the profiled element (10) according todisplacement components which are perpendicular to each other andperpendicular to the longitudinal axis (yy′) of said profiled element,which machine comprises: at least two of the holding dollies (11, 13)disposed close to and one on either side of the at least one machininghead (9), which are capable, in the machining, of securing theslide-holding of the profiled element (10), at least two drive dollies(15, 17) capable of moving longitudinally relative to the frame,disposed one on either side of the holding dollies (11, 13), each drivedolly (15, 17) being provided with a chuck by which, according torequirement, a sliding clamping of the profiled element (10) or alocking of this profiled element can be alternately secured such thatthe relative displacement of the latter relative to the machining head(9) in the longitudinal direction (yy′) is secured, at least in part, bythe displacement of a drive dolly (15, 17) of the at least two drivedollies, control means (16) for operating the displacements of the drivedollies (15, 17) and of the chucks, these control means (16) beingcapable, as a function of various machining phases to be realized, ofsecuring the driving of the profiled element (10) with the aid of one ormore of the drive dollies (15, 17) and of synchronizing the movements ofthe drive dollies, wherein the control means (16) are designed tooperate, in a machining operation, a fixed-connection fastening onto theprofiled element (10) of a first dolly of the at least two drive dollies(17) in an end position and a slide-fastening of a second drive dolly ofthe at least two drive dollies (15), and to secure longitudinaldisplacement of the profiled element (10) by operating displacement ofthe profiled element through that of the drive dolly (17) to which it isfixedly connected and which then forms a “dominant” dolly, and when the“dominant” dolly (17) arrives close to one of the holding dollies (13),the control means (16) operating separation of the dominant dolly (17)from the profiled element (10) and a fixed connection of the seconddrive dolly (15), which second drive dolly then becomes the “dominant”dolly, to the profiled element (10) and which secures the longitudinaldisplacement of the profiled element (10), while the first drive dolly(17) is returned to a preselected position ready to become subsequently“dominant” again.
 2. A machine according to claim 1, wherein, in orderto improve the continuous character of the displacement of the profiledelement (10), the control means being provided such that the profiledelement (10) is driven with the first and second drive dollies (15, 17),then, once this movement is underway, the separation of the first drivedolly (17) arriving close to one of the holding dollies (13) isoperated, the first drive dolly then being returned to a preselectedposition ready to become subsequently “dominant” again.
 3. A machineaccording to claim 1, wherein at least the holding dollies (11, 13) areprovided with a rotary chuck comprising a clamping device for theprofiled element (10) capable of securing positioning of the profiledelement about a longitudinal axis (yy′) of the profiled element.
 4. Amachine according to claim 1, wherein the at least one machining head(9) comprises displacement means acting in the longitudinal direction(yy′) of the profiled element (10).